The invention relates to an arrangement for a gas generator of a motor vehicle occupant protection system, the primary charge of which is arranged in a housing which has at least one opening leading to the housing of the gas-generating propulsion charge.
Protection systems of this type, as air cushions, are known under the name of airbags. The U.S. Pat. No. 4,561,675 describes a gas generator for this purpose which has a central chamber for the primary charge which, by way of openings provided at the circumference of the chamber, is connected with a surrounding additional chamber in which the gas-generating propellant charge is disposed. However, a control of the gas production which depends on the respective ambient temperature is not provided so that by means of this generator, a charging time and a charging ratio of the airbag can only be achieved which is dependent on the ambient temperature.
It is an object of the invention to control the produceable gas volume as a function of the ambient temperature.
This object is achieved according to the invention in that the throughput of the flame jet generated by the primary charge through the opening between the primary charge chamber and the propulsion charge chamber can be adjusted by means of temperature-dependent control elements as a function of the ambient temperature T. Advantageous developments of preferred embodiments of the invention are described below.
The invention is based on the recognition that the burn-up action of the gas-generating propulsion charge is a function of the gas pressure of the primary charge and can therefore be controlled.
It is a special advantage of the control of the propulsion charge according to the invention that the temperature dependence of the gas generator is reduced considerably, whereby the filling ratio of the airbag becomes considerably more uniform within the whole temperature range experienced in use. In addition, the pressure of the propulsion charge chamber is lowered in the range of high temperatures, thereby increasing the operational reliability.
Reference is made to related commonly assigned patent applications Ser. No. 07/526,704, filed May 22, 1990, (based on German Patent Application P 39 21 472.9-21, filed in Germany on June 30, 1989 and German Patent Application P 39 21 473.7-21, filed in Germany on June 30, 1989); and Ser. No. 07/541,954, filed June 22, 1990, (based on German Utility Model No. G 89 09 626.6, filed in Germany on Aug. 11, 1989.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.